# Production Logging Configuration

Comprehensive logging configuration und best practices für Production Deployment des Custom PHP Frameworks.

## Logging Architecture Overview

```
Application Logs → Framework Logger → Log Handlers → Destinations
                        ↓                   ↓             ↓
                   Log Processors      Formatters    Files/Syslog/
                   (Metadata,          (JSON,        External
                    Context,           Line)         Services)
                    Performance)
```

## Log Levels

Das Framework verwendet PSR-3 Log Levels:

| Level     | Severity | Production Use | Description |
|-----------|----------|----------------|-------------|
| emergency | 0        | Always         | System is unusable |
| alert     | 1        | Always         | Action must be taken immediately |
| critical  | 2        | Always         | Critical conditions |
| error     | 3        | Always         | Error conditions |
| warning   | 4        | Recommended    | Warning conditions |
| notice    | 5        | Optional       | Normal but significant condition |
| info      | 6        | Minimal        | Informational messages |
| debug     | 7        | Never          | Debug-level messages |

**Production Recommendation**: `LOG_LEVEL=warning`

## Framework Logger Configuration

### Core Logger Setup

Das Framework nutzt ein hierarchisches Logging-System mit mehreren Kanälen:

**Available Channels**:
- `app` - Application-level logs
- `security` - Security events (OWASP, authentication, authorization)
- `performance` - Performance metrics and slow queries
- `database` - Database queries and errors
- `queue` - Background job processing
- `cache` - Cache operations
- `http` - HTTP requests and responses

### Log Configuration via Environment

```env
# .env.production

# Primary log level (emergency, alert, critical, error, warning, notice, info, debug)
LOG_LEVEL=warning

# Channel-specific log levels (optional)
LOG_LEVEL_SECURITY=info
LOG_LEVEL_PERFORMANCE=warning
LOG_LEVEL_DATABASE=error
LOG_LEVEL_QUEUE=warning

# Log destination (file, syslog, stderr, or combination)
LOG_DESTINATION=file,syslog

# Log file path (relative to project root)
LOG_FILE_PATH=storage/logs/application.log

# Log rotation
LOG_ROTATION_ENABLED=true
LOG_ROTATION_MAX_FILES=14
LOG_ROTATION_MAX_SIZE=100M

# JSON logging (recommended for production)
LOG_FORMAT=json

# Include stack traces in error logs
LOG_INCLUDE_STACKTRACE=true

# Sanitize sensitive data in logs
LOG_SANITIZE_SENSITIVE=true
```

## Log Handlers

### 1. File Handler (Default)

**Location**: `storage/logs/`

**Configuration**:
```php
// src/Framework/Logging/LoggerInitializer.php
use App\Framework\Logging\Handlers\JsonFileHandler;

$fileHandler = new JsonFileHandler(
    filename: $logPath,
    level: LogLevel::WARNING,
    maxFiles: 14,
    maxSize: 100 * 1024 * 1024 // 100MB
);
```

**Log Files Structure**:
```
storage/logs/
├── application.log          # Current application log
├── application-2024-01-15.log
├── application-2024-01-14.log
├── security.log             # Security events
├── performance.log          # Performance metrics
├── database.log             # Database queries
└── error.log                # Error-only log
```

### 2. Syslog Handler

**Integration with System Syslog**:

```php
use App\Framework\Logging\Handlers\SyslogHandler;

$syslogHandler = new SyslogHandler(
    ident: 'michaelschiemer-app',
    facility: LOG_USER,
    level: LogLevel::WARNING
);
```

**Syslog Configuration** (`/etc/rsyslog.d/50-app.conf`):
```conf
# Application logs
local0.*    /var/log/michaelschiemer/app.log

# Security logs
local1.*    /var/log/michaelschiemer/security.log

# Performance logs
local2.*    /var/log/michaelschiemer/performance.log
```

### 3. External Services (Optional)

#### Sentry Integration

```env
# .env.production
SENTRY_DSN=https://xxx@sentry.io/xxx
SENTRY_ENVIRONMENT=production
SENTRY_TRACES_SAMPLE_RATE=0.1
```

#### ELK Stack (Elasticsearch, Logstash, Kibana)

**Logstash Configuration** (`/etc/logstash/conf.d/app.conf`):
```conf
input {
  file {
    path => "/var/log/michaelschiemer/application.log"
    type => "app-logs"
    codec => "json"
  }
}

filter {
  if [type] == "app-logs" {
    json {
      source => "message"
    }
    date {
      match => ["timestamp", "ISO8601"]
    }
  }
}

output {
  elasticsearch {
    hosts => ["localhost:9200"]
    index => "app-logs-%{+YYYY.MM.dd}"
  }
}
```

## Log Processors

Log Processors enrichen log entries mit zusätzlichem Context.

### Available Processors

**1. Performance Processor**:
```php
use App\Framework\Logging\Processors\PerformanceProcessor;

// Adds execution time, memory usage, peak memory
$performanceProcessor = new PerformanceProcessor();
```

**2. Web Info Processor**:
```php
use App\Framework\Logging\Processors\WebInfoProcessor;

// Adds request ID, IP, user agent, URL
$webInfoProcessor = new WebInfoProcessor($request);
```

**3. Exception Processor**:
```php
use App\Framework\Logging\Processors\ExceptionProcessor;

// Adds exception class, file, line, stack trace
$exceptionProcessor = new ExceptionProcessor();
```

**4. Interpolation Processor**:
```php
use App\Framework\Logging\Processors\InterpolationProcessor;

// Replaces placeholders in message with context values
$interpolationProcessor = new InterpolationProcessor();
```

### Custom Processor Example

```php
final readonly class TraceIdProcessor
{
    public function __invoke(LogRecord $record): LogRecord
    {
        $traceId = $this->getDistributedTraceId();

        return $record->withContext([
            'trace_id' => $traceId,
            'span_id' => $this->getCurrentSpanId(),
        ]);
    }
}
```

## Log Formatters

### 1. JSON Formatter (Recommended for Production)

**Output Format**:
```json
{
  "timestamp": "2024-01-15T14:32:45.123456Z",
  "level": "error",
  "channel": "app",
  "message": "Database connection failed",
  "context": {
    "exception": "PDOException",
    "file": "/app/src/Database/Connection.php",
    "line": 42,
    "trace": "..."
  },
  "extra": {
    "request_id": "req_abc123xyz",
    "ip": "203.0.113.42",
    "user_agent": "Mozilla/5.0...",
    "memory_usage": 12582912,
    "execution_time_ms": 234
  }
}
```

**Benefits**:
- Structured data for log aggregation tools
- Easy parsing and filtering
- Machine-readable format
- Standardized timestamps

**Usage**:
```php
use App\Framework\Logging\Formatter\JsonFormatter;

$jsonFormatter = new JsonFormatter(
    prettyPrint: false, // Compact JSON for production
    includeContext: true,
    includeExtra: true
);
```

### 2. Line Formatter (Human-Readable)

**Output Format**:
```
[2024-01-15 14:32:45] app.ERROR: Database connection failed {"exception":"PDOException","file":"/app/src/Database/Connection.php","line":42} {"request_id":"req_abc123xyz","ip":"203.0.113.42"}
```

**Usage**:
```php
use App\Framework\Logging\Formatter\LineFormatter;

$lineFormatter = new LineFormatter(
    format: "[%datetime%] %channel%.%level_name%: %message% %context% %extra%\n",
    dateFormat: "Y-m-d H:i:s",
    allowInlineLineBreaks: false
);
```

## Security Event Logging

### OWASP Security Events

Das Framework nutzt OWASP Application Security Logging für Sicherheitsereignisse:

**Available Event Types**:
```php
use App\Framework\Security\OWASPEventIdentifier;

// Authentication
OWASPEventIdentifier::AUTHN_LOGIN_SUCCESS
OWASPEventIdentifier::AUTHN_LOGIN_FAILURE
OWASPEventIdentifier::AUTHN_LOGOUT_SUCCESS
OWASPEventIdentifier::AUTHN_SESSION_EXPIRED

// Authorization
OWASPEventIdentifier::AUTHZ_PERMISSION_DENIED
OWASPEventIdentifier::AUTHZ_PRIVILEGE_ESCALATION

// Input Validation
OWASPEventIdentifier::INPUT_VALIDATION_FAILURE
OWASPEventIdentifier::INPUT_XSS_DETECTED
OWASPEventIdentifier::INPUT_SQL_INJECTION_DETECTED

// Security Events
OWASPEventIdentifier::SECURITY_INTRUSION_DETECTED
```

**Usage**:
```php
use App\Framework\Security\OWASPSecurityLogger;

$this->owaspLogger->logSecurityEvent(
    new SecurityEventType(OWASPEventIdentifier::AUTHN_LOGIN_FAILURE),
    request: $request,
    context: [
        'username' => $credentials->username,
        'ip_address' => $request->server->getRemoteAddr(),
        'failure_reason' => 'Invalid credentials'
    ]
);
```

**Security Log Format**:
```json
{
  "timestamp": "2024-01-15T14:32:45Z",
  "event_type": "authn_login_failure",
  "severity": "warning",
  "user": "john@example.com",
  "ip_address": "203.0.113.42",
  "user_agent": "Mozilla/5.0...",
  "request_id": "req_abc123xyz",
  "context": {
    "username": "john@example.com",
    "failure_reason": "Invalid credentials",
    "attempt_count": 3
  }
}
```

## Performance Logging

### Slow Query Logging

**Database Slow Queries**:
```php
// Automatically logged via ProfilingConnection
// Threshold: 500ms (configurable)

// Log Entry:
{
  "timestamp": "2024-01-15T14:32:45Z",
  "channel": "database",
  "level": "warning",
  "message": "Slow query detected",
  "context": {
    "query": "SELECT * FROM users WHERE ...",
    "execution_time_ms": 1234,
    "affected_rows": 15000,
    "trace": "..."
  }
}
```

**N+1 Query Detection**:
```php
// Automatically detected via N+1 detection system
{
  "timestamp": "2024-01-15T14:32:45Z",
  "channel": "performance",
  "level": "warning",
  "message": "N+1 query pattern detected",
  "context": {
    "parent_query": "SELECT * FROM posts",
    "repeated_query": "SELECT * FROM comments WHERE post_id = ?",
    "repetition_count": 50,
    "total_time_ms": 2500,
    "suggestion": "Use eager loading or JOIN"
  }
}
```

### Request Performance Logging

```php
// Automatically logged via PerformanceMiddleware
// Threshold: 500ms (configurable)

{
  "timestamp": "2024-01-15T14:32:45Z",
  "channel": "performance",
  "level": "warning",
  "message": "Slow request detected",
  "context": {
    "method": "GET",
    "path": "/api/users",
    "execution_time_ms": 1234,
    "memory_usage_mb": 45,
    "peak_memory_mb": 52,
    "db_queries": 23,
    "cache_hits": 15,
    "cache_misses": 8
  }
}
```

## Log Rotation

### File-Based Rotation

**Configuration**:
```php
// Automatic rotation via JsonFileHandler
new JsonFileHandler(
    filename: 'application.log',
    maxFiles: 14,        // Keep 14 days of logs
    maxSize: 100 * 1024 * 1024  // 100MB per file
);
```

**Rotation Trigger**:
- Daily at midnight (new date in filename)
- When file size exceeds maxSize

**Filename Pattern**: `application-YYYY-MM-DD.log`

### Logrotate Configuration (System-Level)

**`/etc/logrotate.d/michaelschiemer`**:
```conf
/var/log/michaelschiemer/*.log {
    daily
    rotate 14
    compress
    delaycompress
    missingok
    notifempty
    create 0640 www-data www-data
    sharedscripts
    postrotate
        # Reload application if needed
        # docker-compose -f /path/to/docker-compose.yml kill -s USR1 php
    endscript
}
```

## Log Monitoring & Alerting

### Real-Time Log Monitoring

**1. Docker Logs**:
```bash
# Follow all logs
docker-compose logs -f --tail=100

# Filter by service
docker-compose logs -f php

# Filter by log level
docker-compose logs -f | grep -E "(ERROR|CRITICAL|ALERT|EMERGENCY)"

# Search for specific pattern
docker-compose logs -f | grep "Database connection failed"
```

**2. File-Based Monitoring (tail)**:
```bash
# Follow application log
tail -f storage/logs/application.log | jq '.'

# Filter errors only
tail -f storage/logs/application.log | jq 'select(.level == "error")'

# Filter security events
tail -f storage/logs/security.log | jq 'select(.event_type | startswith("authn"))'
```

### Alerting Configuration

**1. Log-Based Alerts (with Logstash/Elasticsearch)**:

**Watcher Alert Example** (Elasticsearch):
```json
{
  "trigger": {
    "schedule": {
      "interval": "1m"
    }
  },
  "input": {
    "search": {
      "request": {
        "indices": ["app-logs-*"],
        "body": {
          "query": {
            "bool": {
              "must": [
                { "range": { "@timestamp": { "gte": "now-5m" } } },
                { "terms": { "level": ["error", "critical", "alert", "emergency"] } }
              ]
            }
          }
        }
      }
    }
  },
  "condition": {
    "compare": {
      "ctx.payload.hits.total": {
        "gt": 10
      }
    }
  },
  "actions": {
    "send_email": {
      "email": {
        "to": "ops@example.com",
        "subject": "High Error Rate Detected",
        "body": "More than 10 errors in the last 5 minutes"
      }
    }
  }
}
```

**2. Custom Alert Script**:

```bash
#!/bin/bash
# /usr/local/bin/log-alert-check.sh

LOG_FILE="/var/log/michaelschiemer/application.log"
ALERT_EMAIL="ops@example.com"
ERROR_THRESHOLD=10

# Count errors in last 5 minutes
ERROR_COUNT=$(grep -c '"level":"error"' <(tail -n 1000 "$LOG_FILE"))

if [ "$ERROR_COUNT" -gt "$ERROR_THRESHOLD" ]; then
    echo "High error rate detected: $ERROR_COUNT errors" | \
        mail -s "ALERT: High Error Rate" "$ALERT_EMAIL"
fi
```

**Cron Job**:
```cron
# Check every 5 minutes
*/5 * * * * /usr/local/bin/log-alert-check.sh
```

## Log Sanitization

### Sensitive Data Protection

Das Framework sanitiert automatisch sensitive Daten in Logs:

**Automatically Redacted Keys**:
- `password`, `passwd`, `pwd`
- `token`, `access_token`, `refresh_token`
- `secret`, `api_key`, `api_secret`
- `authorization`, `auth`
- `credit_card`, `cc_number`, `cvv`
- `ssn`, `social_security`

**Example**:
```php
$logger->info('User authentication', [
    'username' => 'john@example.com',
    'password' => 'secret123',  // Will be logged as '[REDACTED]'
    'api_key' => 'sk_live_xxx'  // Will be logged as '[REDACTED]'
]);
```

**Custom Sanitization**:
```php
use App\Framework\Logging\LogSanitizer;

$sanitizer = new LogSanitizer(
    sensitiveKeys: ['custom_secret', 'internal_token']
);

$sanitizedContext = $sanitizer->sanitize($context);
```

## Production Logging Best Practices

### 1. Log Level Management

**DO**:
- Use `warning` level in production for operational awareness
- Use `error` for failures that need investigation
- Use `critical`/`alert`/`emergency` for immediate action needed

**DON'T**:
- Never use `debug` level in production (performance impact)
- Avoid `info` level for high-frequency events
- Don't log sensitive data (passwords, tokens, PII)

### 2. Structured Logging

**DO**:
- Use JSON format for machine parsing
- Include consistent context (request_id, user_id, ip)
- Add relevant metadata (execution_time, memory_usage)
- Use consistent field names across all logs

**DON'T**:
- Avoid unstructured string concatenation
- Don't mix log formats (JSON vs plain text)
- Avoid dynamic field names

### 3. Performance Considerations

**DO**:
- Implement asynchronous logging for high-traffic systems
- Use log rotation to prevent disk space issues
- Monitor log volume and adjust thresholds
- Cache logger instances

**DON'T**:
- Never perform expensive operations in log statements
- Avoid logging in tight loops
- Don't log entire objects (use specific fields)

### 4. Security

**DO**:
- Log all authentication and authorization events
- Log security exceptions (SQL injection, XSS attempts)
- Include request context for security analysis
- Implement log integrity checks

**DON'T**:
- Never log passwords, tokens, or sensitive PII
- Avoid logging entire request/response bodies
- Don't expose internal system paths in production logs

## Troubleshooting

### Problem: Logs not being written

```bash
# Check log directory permissions
ls -la storage/logs/

# Fix permissions
chmod 755 storage/logs/
chmod 644 storage/logs/*.log

# Verify logger configuration
php console.php config:check --key=LOG_LEVEL

# Test logging
php console.php log:test --level=error
```

### Problem: Log files growing too large

```bash
# Check log file sizes
du -sh storage/logs/*

# Manually rotate logs
mv storage/logs/application.log storage/logs/application-$(date +%Y%m%d).log

# Compress old logs
gzip storage/logs/application-2024*.log

# Force logrotate
logrotate -f /etc/logrotate.d/michaelschiemer
```

### Problem: Performance degradation due to logging

```bash
# Increase log level to reduce volume
# .env: LOG_LEVEL=error

# Disable verbose processors
# Remove WebInfoProcessor, PerformanceProcessor in production

# Use asynchronous logging
# Implement QueuedLogHandler for high-traffic scenarios
```

## See Also

- **Security Patterns**: `docs/claude/security-patterns.md`
- **Performance Monitoring**: `docs/claude/performance-monitoring.md`
- **Error Handling**: `docs/claude/error-handling.md`
- **Deployment Guide**: `docs/deployment/production-prerequisites.md`